The acceptance of cistern systems as a source of potable water and as a possible
source for non-domestic use is dependent upon the quality maintained within the
entire system. Microbial levels measured within a cistern system are reliable
indicators of water quality and of deteriorations that may give rise to offensive
odors and tastes. The number of microorganisms commonly found within most contemporary
cistern systems is usually lower than surrounding surface waters but these microbial
levels may still be unacceptable for many alternative uses. Our laboratory is
studying the bacterial populations growing and residing within cistern systems.
During periods of rainfall collection and heavy usage, the microbial populations
of single-chamber cistern systems do not decrease significantly during subsequent
storage (self-purify). The storage of rain water in cistern systems may actually.be
conducive to the growth of certain bacterial strains in numbers beyond those found
in natural water sources. Our studies have shown that certain types of maintenance
of individual, single-chamber catchment systems may actually increase the levels
of certain microbial strains when compared to similar systems receiving no.treatment
at all. More work is required to identify those parameters necessary for the proper
storage and maintenance of high quality cistern water.